Arrangement at self expanding booms

ABSTRACT

A valve mechanism for self-expanding booms. The mechanism is preferably a mechanical expansion device that folds out the boom so that air flows into the boom to fill the boom. When the boom is folded, the air is pressed out of the boom. A novel feature is an automatic control mechanism that is adapted to permit an inflow of air into the boom when the boom is expanded and to permit an outflow of air when the boom is collapsed, rolled up and stored. The control mechanism is affected by the relative position between the valve mechanism and other parts of the boom when the boom is in the expanded or collapsed position.

TECHNICAL FIELD

This invention relates to self-expanding booms and more particularly tovalve mechanisms. The valve mechanisms ensure an inflow of air when theboom is expanded and an outflow of air when the boom is rolled up.

BACKGROUND INFORMATION

A plurality of air openings are defined at the upper end of the selfexpanding booms of the prior art. Valves are placed in the openings topermit an air inflow when the boom is expanded from a collapsed storageor transportation mode. Air disposed inside the boom is also permittedto flow out through the openings when the boom is taken up, collapsedand rolled up on transportation or storage rolls or a similar devices.

While employing the boom, that is when the boom is floating in thewater, the air openings must be closed to prevent water from flowinginto the boom and to prevent air from undesirably flowing out of theboom sections so that the sections sink.

In an embodiment of the prior art, a plurality of tube protrusion orsimilar devices are placed along the upper edges of the boom. Theprotrusions are equipped with an outward shiftable or rotatable lockingmechanism. In one position, the locking mechanism permits an uninhibitedinflow and outflow of air and in a different position the protrusion isclosed.

This type of air openings require manual adjustments both when the boomis laid down and when the boom is taken up and rolled up.

One object of the present invention is to provide a new device that,without the need for manual adjustments, permits uninhibited inflow ofair when the boom is expanded and prevents water from flowing in whenthe boom is in use. Additionally, the air inside the boom must bepermitted to freely flow out of the boom when the boom is taken up andcollapsed.

SUMMARY OF THE INVENTION

An object of the present invention is to take advantage of the inherentchanges of the position of the various parts or details to shift thevalve body into and out of a closed position when the boom is expandedand collapsed, respectively.

In the preferred embodiment of the present invention, this object isachieved by attaching one end of a bendable member to the valve body.The other end of the bendable member is attached to an expansionmechanism disposed inside the boom or to another part disposed insidethe boom. The part is shiftable relative to the valve mechanism when theboom is expanded and collapsed. In this way, when the boom is collapsed,the bendable member, which may be a cord, is extended to shift the valvebody from its sealing and air outflow inhibiting position so that theboom may effectively be emptied of air. However, when the boom is laidout and the expansion devices are permitted to expand, the pullingmovement of the cord stops and the valve mechanism returns to its restposition so that air may flow into the boom.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the present invention is described below withthe reference to the following enclosed drawings wherein:

FIG. 1 is a perspective view and a partly opened section view of a boomaccording to the preferred embodiment of the present invention;

FIG. 2 is a side view in partial cross-section of the invention shown inalong line 1--1 of FIG. 1.

FIG. 3 is an enlarged side view in partial cross-section of the valvemechanism attached to the upper portion of the boom wherein the valvemechanism is in a first position; and

FIG. 4 is a side view in partial cross-section of a portion of the viewof FIG. 3 wherein the valve body is in a second position.

DETAILED DESCRIPTION

With reference to the figures, a boom of the present invention has amain portion 1 and a so called skirt 2 protruding downwardly. The boomconsists of a bendable impervious material such as a woven textilereinforced plastic material. A number of spring biased expansion devices3 are disposed within the boom. The expansion devices 3 have thefunction of separating walls 4 so that air may be sucked into the boomwhen the boom is expanded from an almost flat collapsed position afterthe boom has been removed from a transport and storage reel. When, onthe other hand, the boom is collapsed after use, the expansion devices 3are collapsed against the biasing forces of the springs so that thewalls 4 are moved together and the air captured inside the boom isremoved. The collapsed position is normally achieved by winding the boomon to a storage reel. Both the air inflow and the air outflow areconducted through a valve mechanism 5. The valve mechanisms is usuallybonded to a pipe shaped support stud 6 that is welded or bonded to theplastic material at the upper portion of the boom where the upwardlysloping walls 4 are joined to one another.

According to the present invention, the valve mechanism 5 functionsautomatically without any manual intervention so that air is permittedto flow into the boom when the boom is expanded and out of the boom whenthe boom is collapsed and otherwise prevents water, essentially also airfrom passing through.

The automatic valve mechanism 5 includes a valve body 7 and a biasingspring 8 cooperating therewith so that the valve body 7 is shiftablebetween a first position defined by the spring 8 and a perforated lid 9forming an abutment, FIG. 3, so that air is permitted to be sucked inthrough one or a plurality of passages 11 provided with check valvemeans 10, and a second position, FIG. 4, into which the valve member 5is shifted by the influence of tension of a flexible member in the formof a cord 12 against the biasing force of the spring 8, in which air isallowed to flow out through the perforated lid 9 by another check valvemeans.

Below is a more detailed description of the valve mechanisms 5. Thevalve mechanisms 5 includes a valve housing 14 having a narrow portion15 at a lower end thereof. The narrow portion is adapted to be insertedinto and glued to the support stud 6. Two or more radially disposedopenings 16 are defined in the housing 14. Each opening form a part ofthe passage 11. A free end of the housing 14 has an outward flange 17having an outward protrusion 18 in operative engagement therewith. Anaxially protruding portion 20 of the lid 9 has an inward groove 19defined therein that is adapted to engage the protrusion 18. The lid 9is presumably made of a plastic material or a similar material that hasa certain elasticity.

The valve body 7 is shaped like a casing and has a narrow portion 21disposed at one end thereof so that a space is defined between theportion 21 and the inside of the valve housing 14 to receive the spring8. The narrow end of the casing is open and includes a fasteningmechanism 22 to hold a bendable member such as the cord 12. The oppositeend of the casing is perforated or has a grate shaped end wall enclosure23. One end of a tongue shaped check valve member 13 is attached to anedge portion of the end enclosure 23 so that the valve member 13 will beable to function as a check valve. It is important that the tongue,which is made of a suitable rubber material or a similar material islight so that it may be bent by a weak air flow. For this reason, thematerial is porous.

In the casing of the valve body 7 are two or possibly more than tworadially facing openings 24 defined. Only one opening is shown. Thecheck valve mechanism 10 is attached to the inside of the casingadjacent the openings 24. Similarily with the check valve 13 at the endof the valve housing 14, the check valve mechanism 10 includes a movabletongue 25 that is made of a soft flexible material and is bendable by anair stream. Attached around each opening 24 is an elastic seal (notshown). This seal may be an O-ring or have a similar shape, and bepressed, in a suitable way, into a groove to form around the opening 24a seal sealingly engaging the inside of the valve housing 14.

FIG. 3 shows the valve 5 in a rest position which means that the cord 12is slack and the spring 8 is urging the valve body 7 upwardly so thatthe back valve member 13 at the perforated upper end is held against theinside of the lid 9. In this way, the upper opening is mechanicallyclosed for air flow in both directions. If, when the valve is in thisposition, a pressure lower than the atmospheric is created inside theboom, which occurs when the boom is expanded, air is sucked in throughthe passages 11 that is through the openings 16 and 24 by the checkvalve mechanism or tongue 25 to fill the boom. The air can not flow backout because the tongues of the back valve mechanism close the passages.

The cord 12 extends from the valve mechanism through springs 27 disposedat two of the expansion devices 3--in some cases, one spring issufficient--and one end of the cord is attached to the wall of the boom.When the boom is folded together or collapsed, the springs 27 of theexpansion devices are stretched. As a result of the lengthening of thesprings 27 when the boom is collapsed, the cord 12 is put under tensionbecause one end of the cord is secured to the boom and the other end ofthe cord 12 is attached to the valve body 7. As a consequence, the cord12 pulls the valve body 7 downwardly against the biasing force of thespring 8. Because the valve body 7 is shifted downwardly, the upper endof the valve body 7 is removed from the lid 9 so that the tongue 13 isbent outwardly as air flows out as a result of the high pressure createdinside boom by the collapse of the boom.

In the preferred embodiment of the present invention, the valve housing14 has two pair of radially disposed openings 16 and 16' definedtherein. The openings are positioned at different levels. The reason forthis is that when an expansion operation is started, air must be able toenter into the boom to permit proper expansion of the boom. In thebeginning stage when the valve body is in the position as shown in FIG.4, air may be sucked in through openings 16'. However, due to thecontraction of the springs 27, the tensioning of the cord 12 stops andwhen the valve body 7 reaches the position shown in FIG. 3 air flowsinto the openings 16.

To make it easier to adjust the length of the cord 12 and to eliminatethe risk of tearing off the cord 12 or that the valve mechanism 5 isdamaged by an unexpectedly powerful tensioning of the cord 12, it isdesirable, as indicated in FIG. 2, to provide the cord 12 with anelastic mid portion 28. The mid portion may be a spring or a similardevice that is positioned at a suitable part of the cord.

While the present invention has been described with reference topreferred embodiments, it is to be understood that certain substitutionsand alterations may be made thereto without departing from the spiritand scope of the invention as set forth in the appended claims.

What is claimed is:
 1. A device providing ventilation of a selfexpanding boom that ensures an air inflow into the boom arranged as asubstantially sealed container when the boom is expanded and thatensures an air outflow when the boom is collapsed, the device comprisingan automatic valve means having a valve body which, as a result ofrelative movement between portions of the boom, is shiftable between afirst position in which the valve body permits air inflow into the boomand a second position in which the valve body permits air outflow fromthe boom; and further including a flexible member connected between theboom and the valve body in such a way that the flexible member issubstantially slack when the boom is expanded and the valve body is inits first position whereas, when the boom is collapsed, the flexiblemember is tightened and displaces the valve body to its second positionto permit air outflow from the boom.
 2. The device according to claim 1,wherein the automatic valve means in the second position of the valvebody is arranged to permit air outflow from the boom only as long asthere is a pressure above atmospheric pressure inside the boom, whereasthe automatic valve means in the first position of the valve body isarranged to permit air inflow to the boom in the presence of partialvacuum caused by expansion of the boom.
 3. The device according to claim1, wherein the flexible member includes an elastic intermediary portionto absorb tension forces beyond those absorbed by the valve body.
 4. Thedevice according to claim 1, wherein the automatic valve means furtherincludes an essentially substantially tube shaped housing, the valvebody being essentially tube shaped and axially movable inside thehousing, the valve body and the housing have cooperating openingspermitting the air inflow when the boom is expanded and cooperatingopenings permitting air outflow when the boom is collapsed, at leastsome of the cooperating openings have check valve means permitting flowof air only in one direction.
 5. The device according to claim 4,wherein each check valve means includes a tongue made of an elasticmaterial, an edge portion of each tongue being attached to the valvebody.
 6. The device according to claim 4, further including a sealingdevice encompassing each cooperating opening in the valve body tosealingly engage with an inside wall of the valve housing.
 7. The deviceaccording to claim 4, wherein each cooperating inflow opening in thevalve body cooperates with one respective cooperating inflow opening inthe valve housing when the valve body is in its first position andcooperates with another respective cooperating inflow opening in thevalve housing when the valve body is in its second position.